The Jamaican mother of a seven-year-old girl shot dead along with her father in a London bedsit, made an emotional appeal for help in solving her murder.

Toni-Ann Byfield and her father, Bertram, were killed on Sunday. Police believe Toni-Ann was murdered because she saw her father's killer.

"Whoever did this left my sons without a sister and a father," Toni-Ann's mother, Rosalyn Christine Richards said during a news conference in Jamaica yesterday. "I beg anyone who knows anything to come forward to the police."

Toni-Ann was shot once in the back, apparently after witnessing her father's killing.

Mr Byfield, a Briton raised in Jamaica, served nine years in a British prison for dealing crack cocaine.